大荔潜水含水层中氟的赋存规律及水化学成因

大荔县地处渭河断陷盆地东部,潜水中氟含量较高,氟的赋存受水文,气候,地形地貌、地质背景、水文地质、水文地球化学等多种因素的制约,根据浅层地下水调查资料采用美国地质调查局的PHREEQC软件来研究地下水中氟赋存规律.该地区降雨量小,蒸发强烈,高氟水的成因可分为,蒸发浓缩型和溶滤富集型.岩性主要为黏土、亚黏土、细砂,孔隙小,富含氟的矿物成分为地下水中高氟提供了丰富的物质来源.地下水水位埋深浅,包气带中毛细上升高度高,导水性差,多层交互含水层结构为高氟地下水提供了得天独厚的赋存条件.结合水文地球化学的作用,研究了氟与其主要络合离子的存在形式和组分浓度以及它们的矿物来源的溶解-沉淀情况,来揭示氟在地下水径流方向上的演化规律.     

Mercury pollution from artisanal mercury mining in Tongren, Guizhou, China

Concentrations of total Hg (T-Hg) were measured in mine waste, stream water, soil and moss samples collected from the Tongren area, Guizhou, China to identify potential Hg contamination to local environments, which has resulted from artisanal Hg mining. Mine waste contained high T-Hg concentrations, ranging from 1.8 to 900 mg/kg. High concentrations of Hg were also found in the leachates of mine waste, confirming that mine waste contains significant water-soluble Hg compounds. Total Hg distribution patterns in soil profiles showed that top soil is contaminated with Hg, which has been derived from atmospheric deposition. Data suggest that organic matter plays an important role in the binding and transport of Hg in soil. Elevated T-Hg concentrations (5.9–44 mg/kg) in moss samples suggest that atmospheric deposition is the dominant source of Hg to local terrestrial ecosystems. Concentrations of T-Hg were highly elevated in stream water samples, varying from 92 to 2300 ng/L. Particulate Hg in water constituted a large proportion of the T-Hg and played a major role in Hg transport. Methyl–Hg (Me–Hg) concentrations in the water samples was as high as 7.9 ng/L. Data indicate that Hg contamination is dominantly from artisanal Hg mining in the study area, but the extent of Hg contamination is dependent on the mining history and the scale of artisanal Hg mining.     

渗流的PFC-CFD耦合细观数值模拟

本文针对饱和多孔介质中渗流特点,在分析渗流连续介质力学模型的基础上,采用描述多孔介质中固相颗粒和液相流体耦合的细观力学模型,其中固相颗粒采用离散元的颗粒流理论(PFC)模拟,液相流体通过求解平均Navier-Stokes方程的计算流体动力学(CFD)技术计算,并利用建议的模型对二维渗流问题进行了模拟验证。数值模拟结果表明,采用PFC-CFD耦合细观力学模型能够描述从低雷诺流到高雷诺流范围很大的流体运动,可以用于多孔介质中的渗流问题分析。     

Numerical Simulation of Bed Separation Development and Grout Injecting into Separations

In this paper, the Cosserat theory that has been incorporated into a three dimensional finite element code COSFLOW, is applied to analyze the development of bed separations in the layered overburden and grout injection into the bed separations. The mechanism of bed separation development during the longwall mining is investigated. A parametric study is carried out to investigate the effect of major factors including hard rock grade, panel height and panel weight on bed separation development. Based on the modeling, a conceptual model to describe the development process of bed separation is proposed. The effect of grout injecting into the bed separations on subsidence reduction is also studied and the conclusion agrees well with the common realization.     

应用全波场正演模拟进行川西深层海相地震勘探工程设计参数论证的研究

这里讨论了川西深层海相地震勘探工程设计的参数论证问题.在分析该区以往地震勘探工程设计的基础上,以现有地质认识为基础构建正演模型,利用Tesseral软件的正演模拟分析功能,进行地震采集参数的论证和观测系统的优化设计.地震数据采集实验结果表明,经过正演模拟优化的观测系统,能大幅度地改善地震数据采集的品质.     

中国西太平洋海域1′×1′垂线偏差模型及精度评估

联合多种测高数据和重力异常数据,设计了观测点距离和测高精度融合的定权方法,采用最小二乘方法和Vening-Meinesz公式,分别构建了西太平洋海域(0°N—40°N,105°E—145°E)1′×1′网格化垂线偏差数字模型。选取两个不同特征区域,将垂线偏差的两个数字模型和EGM2008模型三者进行相互比较分析。结果表明:卯酉分量η的均方根差大于子午分量ξ的均方根差,海底地形复杂的南海特征区域的垂线偏差均方根差大于西太平洋中部的均方根差,构建的两个垂线偏差模型总体均方根差优于1.6″。     

Assessment of second- and third-order ionospheric effects on regional networks: case study in China with longer CMONOC GPS coordinate time series

Higher-order ionospheric (HOI) delays are one of the principal technique-specific error sources in precise global positioning system analysis and have been proposed to become a standard part of precise GPS data processing. In this research, we apply HOI delay corrections to the Crustal Movement Observation Network of China’s (CMONOC) data processing (from January 2000 to December 2013) and furnish quantitative results for the effects of HOI on CMONOC coordinate time series. The results for both a regional reference frame and global reference frame are analyzed and compared to clarify the HOI effects on the CMONOC network. We find that HOI corrections can effectively reduce the semi-annual signals in the northern and vertical components. For sites with lower semi-annual amplitudes, the average decrease in magnitude can reach 30 and 10 % for the northern and vertical components, respectively. The noise amplitudes with HOI corrections and those without HOI corrections are not significantly different. Generally, the HOI effects on CMONOC networks in a global reference frame are less obvious than the results in the regional reference frame, probably because the HOI-induced errors are smaller in comparison to the higher noise levels seen when using a global reference frame. Furthermore, we investigate the combined contributions of environmental loading and HOI effects on the CMONOC stations. The largest loading effects on the vertical displacement are found in the mid- to high-latitude areas. The weighted root mean square differences between the corrected and original weekly GPS height time series of the loading model indicate that the mass loading adequately reduced the scatter on the CMONOC height time series, whereas the results in the global reference frame showed better agreements between the GPS coordinate time series and the environmental loading. When combining the effects of environmental loading and HOI corrections, the results with the HOI corrections reduced the scatter on the observed GPS height coordinates better than the height when estimated without HOI corrections, and the combined solutions in the regional reference frame indicate more preferred improvements. Therefore, regional reference frames are recommended to investigate the HOI effects on regional networks.     

一种基于占有率反馈的虚拟网络映射算法

网络虚拟化技术通过对物理资源的抽象,可以有效解决现有互联网架构中存在的网络结构僵化、可扩展性差等问题.虚拟网络映射问题是指将用户发送的所有虚网请求映射到底层物理网络中,同时还要满足虚网请求中对各个资源的限制要求（如节点计算能力、链路带宽等）.从节点负载平衡的角度出发,在基于就近原则的虚网映射算法基础上,引入节点负载平衡的反馈机制,引导各个虚网请求更均匀地映射到底层物理网络中.另外,在k短路径算法机制中引入了当前链路资源占有率作为评价参考标准,这样可以尽可能均匀地分散链路压力.同时,在检验链路资源是否满足虚网请求的过程中,由于优先选中的链路资源占有率低,所以算法映射成功率高,映射耗时更短,虚拟网络映射效率得到了有效提高.     

Optimization of simulation and visualization analysis of dam-failure flood disaster for diverse computing systems

Simulation and subsequent visualization in a network environment are important to glean insights into spatiotemporal processes. As computing systems become increasingly diverse in hardware architectures, operating systems, screen sizes, human–computer interactions and network capabilities, effective simulation and visualization must become adaptive to a wide range of diverse devices. This paper focuses on the optimization of simulation and visualization analysis of the dam-failure flood spatiotemporal process for diverse computing systems. First, an adaptive browser/server architecture of the dam-failure simulation application was designed to fill the hardware performance and visualization context gap that exists within diverse computing systems. Second, a data flow and an optimization method for multilevel time-series flood data were given to provide more support to network simulation, visualization and analysis on diversified terminals. Finally, a user interaction friendly and plugin-free prototype system was developed. The experiment results demonstrate that the methods addressed in this paper can cope with the challenge in simulation, visualization and interaction of a dam-failure simulation application on diversified terminals.     

2000年河西秋、冬季沙尘暴成因分析及预报着眼点

文中从天气气候背景及天气学、动力诊断等方面 ,分析 2 0 0 0年秋、冬季河西大风和沙尘暴天气的形成原因 ,分析结果表明 ,几次大风、沙尘暴过程都是在高空 5 0 0hPa环流形势由纬向环流向径向环流调整的过程中 ,西西伯利亚强冷空气沿西北气流迅速南下 ,在蒙古地面热低压强烈发展的有利的热力和动力条件下发生的。同时 ,今年秋、冬季河西气温明显偏高 ,降水偏少以及河西地区特殊的地理环境 ,加剧了大风和沙尘暴天气的出现频次和强度。通过分析 ,初步总结出了此类天气的预报着眼点。